twoway (hist sh_R90_s if s_in_sample==1 & n_s==1, yla(,nogrid) frac lcolor(gs12) fcolor(gs12)) ///
(hist sh_R90_s if s_in_sample==1 & n_s==1 & sh_R90_s>0 , frac fcolor(none) lcolor(black)), graphregion(color(white)) ///
 legend(off) xtitle("" )
graph export "${figures}\FigureC2.pdf", replace 